.TH FL_poll 3 "Dec 2000" "Flush Spread" "User Manuals"
.SH NAME
FL_poll \- returns the amount, in bytes, of activity on a connection.
.SH SYNOPSIS
.B #include <fl.h>

.BI "int FL_poll(mailbox " mbox ");"
.SH DESCRIPTION
.B FL_poll
is a way to poll the connection represented by
.I mbox
to see if there is any activity on that connection.  

.BR NOTE ,
however that activity does
.B NOT
necessarily mean that a message is available to be read, as in Spread.
Only a call to FL_more_msgs that returns a positive number of buffered
messages or a DONT_BLOCK receive call can check for sure to see if a
message is now available to be read.  If you don't use either of these
semantics, then you may enter into a blocking receive call, which can
sometimes be dangerous (see FL_flush).
.SH "RETURN VALUES"
Returns the number of bytes of activity currently on the connection,
or one of the following errors ( < 0 ):
.TP
.B ILLEGAL_SESSION
The connection represented by 
.I mbox
is illegal, usually because it is not active.
.SH AUTHOR
John Schultz <jschultz@cnds.jhu.edu>
